This invention relates generally to a syngas cooler, and, more particularly, to a heat recovery system for use with a syngas cooler.
At least some known syngas coolers include platens and a tube wall to facilitate heat transfer from a syngas flow to a fluid flowing within the platens and/or tube wall. The platens in such syngas coolers are circumscribed by the tube wall. Known tube walls are designed to be gas-tight such that the syngas is effectively retained within the tube wall. As such the syngas contacts the tube wall rather than an outer shell of the cooler. Generally, the cooler outer shells are not as thermally tolerant as the tube wall.
As least some known syngas coolers include a plurality of platen supply lines and a plurality of separate tube wall supply lines that are each coupled between the tube wall and the outer shell. The platen supply lines couple to a platen lower manifold. The tube wall supply lines are each coupled to a separate tube wall lower manifold such that the platens and the tube wall are supplied with heat transfer fluid through respective manifolds. In at least some known syngas coolers, the platen lower manifold is positioned upstream and radially inward from the tube wall lower manifold. In such coolers, the platen supply lines must pass through the tube wall to be coupled to the platen lower manifold. Unfortunately, such penetrations through the tube wall may undesirably allow heated syngas to flow through the tube wall and contact the outer shell, which may induce thermal stresses and/or premature wear to the outer shell of the cooler. To facilitate reducing syngas leakage, at least some known syngas coolers include a seal coupled between the platen supply line and the tube wall where each supply line passes through the tube wall. However, such seals may leak and allow heated syngas to escape from the tube wall.